/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.optimize.info;

import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.constant.ClassConstant;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.instruction.*;
import proguard.classfile.instruction.visitor.InstructionVisitor;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.ClassVisitor;
import proguard.optimize.OptimizationInfoClassFilter;

/**
 * This InstructionVisitor marks all classes that are used in an 'instanceof' test by any of the instructions that it
 * visits.
 *
 * @author Eric Lafortune
 */
public class InstanceofClassMarker extends SimplifiedVisitor
    implements InstructionVisitor, ConstantVisitor, ClassVisitor {
    private final OptimizationInfoClassFilter filteredClassMarker = new OptimizationInfoClassFilter(this);

    // Implementations for InstructionVisitor.

    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset,
        Instruction instruction) {}

    public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset,
        ConstantInstruction constantInstruction) {
        if (constantInstruction.opcode == InstructionConstants.OP_INSTANCEOF) {
            clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this);
        }
    }

    // Implementations for ConstantVisitor.

    public void visitClassConstant(Clazz clazz, ClassConstant classConstant) {
        classConstant.referencedClassAccept(filteredClassMarker);
    }

    // Implementations for ClassVisitor.

    public void visitAnyClass(Clazz clazz) {
        setInstanceofed(clazz);
    }

    // Small utility methods.

    private static void setInstanceofed(Clazz clazz) {
        ProgramClassOptimizationInfo.getProgramClassOptimizationInfo(clazz).setInstanceofed();
    }

    public static boolean isInstanceofed(Clazz clazz) {
        return ClassOptimizationInfo.getClassOptimizationInfo(clazz).isInstanceofed();
    }
}